Networking:

eth_set eth0 100f (sets the speed and duplex of eth0 to 100Mb Full Duplex – survives a reboot)

ethtool eth0 (displays the settings for interface eth0 such as speed/duplex etc

netstat -rn (to show the routing table of your device)

ifconfig ( to show the list of available interfaces)

tcpdump -i eth0 -s 1500 net 10.200.1.0/24 -w/var/tmp/xxw.pcap

* If you want to filter based on the network address, you should put as above, if filter based on host, change it to ‘host 10.200.1.1’.
**The -s 1500 indicate the normal 1500 size packet you want to capture. If you don’t define 1500, the packets captured will show incomplete details.
***-w is used to save the files to a specific folder. By defining the file extension with .pcap, you’d be able to double click the file to open it via ethereal.

netstat -rn | more (displays the routing table, without resolving names – if you wish to display it per page, use | more at the end of your command line)

About Rich Bibby

Rich Bibby is a UK based Network Engineer, working mainly with Cisco, Juniper and Arista gear in the enterprise LAN, WAN and Data Centre space. Aside from route/switch/firewalling, he is interested in open source network monitoring and management tools, and exploring the possibilities that automation and programmability bring to networking.
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